User guide › grABloop for teachersVersion 1

grABloop for teachers#

How a music teacher prepares a song for a student, marks the passages to practise, sets the practice plan, hands it over, and keeps a class of songs in order. Everything here is in grABloop today unless the section says otherwise.

1. Prepare a song#

• Import the recording the student will learn from: an audio file (MP3, WAV, FLAC, M4A, AAC, OGG, Opus, AIFF) or a video (MP4, MOV, M4V; MKV and WebM give their sound). grABloop copies the file into its library and never touches the original. Drop files on the window, use Open With / Share from the system, or import a whole folder at once.
• Several recordings of one song live in one project as versions: the original, a slower cover, your own backing track, the student's recording of last week. Each version keeps its own loops, bookmarks and settings; one is marked the original (★).
• Cut the song down. "Trim to loop" keeps only the passage inside a loop and frees the disk space; "New song from loop" cuts the passage into a project of its own and leaves the song whole. "Remove silence" takes the silence off the start and end. All of it is lossless and undoable; your file is never changed.
• Edit details: title, artist, album, and for each version the performer, year and a label ("live", "backing track"). Tags come from Settings ▸ Tags and are chosen in Edit details.
• Notes: free text with the song, for fingerings, what to listen for, the homework.

2. Mark the passages#

• Loops are named, coloured A–B regions; a song may have as many as you need, overlapping if you like. Set A and B while the song plays (keys or the flags on the waveform), drag them to the exact note, zoom in to the sample. The seam from B back to A is click-free.
• Each loop can carry its own settings: speed, pitch, sound tools and equaliser, a gap between repeats (seconds of silence to think, or to play it back), a count-in before the first pass, and how many times it repeats before stopping. With "Only for loop" the loop's own speed and pitch apply while it plays and the rest of the song keeps the project's. A warm-up loop at 60 %, the hard bar at 50 % with a two-second gap, the whole chorus at 90 %: one song, three practice settings, remembered forever.
• Bookmarks are named positions: "solo starts", "watch the key change", "from here next week". Jump between them with keys; the first nine by number.
• Pitch presets are named tunings per song: "E♭ tuning", "Maria's key", "A = 442". The student switches between them while the song plays; "as recorded" is always there.

3. Set the practice plan#

• Speed and pitch, independently: 20–200 % without changing the pitch; ±24 semitones with cents and a reference pitch for old records, without changing the speed. The engine is chosen for a learner's ears (ADR-005); two engines are offered and can be compared live.
• The loop trainer raises (or lowers) the speed by itself: start at 60 %, go to 100 % in steps of 5 % every 3 repeats, or every 30 seconds. After each pass the student marks it clean or not; the step advances only after N clean passes in a row and drops back one step on a stumble. Trainer presets ("Warm-up 70→100 by 5 every 2") are kept once and used on any loop; a loop remembers which preset it uses.
• Hearing the part. The sound tools work on the song before it is slowed: mono, left or right channel only, swap, a centre cancel for "take the voice down" and a stereo width control; then a ten-band equaliser with presets such as lifting a solo or cutting the bass. Sound presets are named and reused; a loop can have its own.
• Video stays in sync at any speed and pitch, docked beside the waveform or full screen; step through it frame by frame to study a fingering or a bowing.

4. Lyrics and chords#

• Each song keeps one lyric sheet with chords placed above the syllables (ChordPro inside; paste "chords above lyrics" text and grABloop converts it). Credits (lyrics by, music by, original key) go with it.
• Chords follow the pitch shift: transpose the song down three semitones and the sheet shows the chords in the new key, with a capo option. Tap a chord for its guitar shape.
• Lines for a loop: pick the lines a loop covers; while it plays they carry its colour and stay in view. The sheet sits beside the player or, on a phone, on its own screen with a mini player.

5. Hand it to the student#

• Export a bundle (.grabloop): one file with the song, each version's recording, every loop with its settings, bookmarks, pitch presets, trainer presets the loops use, lyrics, notes and tags. The student imports it with a double-click or Open With; grABloop merges it into their library, so a second bundle for the same song adds and updates your loops and never deletes anything of theirs. The export asks once per library to confirm you have the right to share the recordings; a bundle of your own backing track or a public-domain recording is the simple case.
• The same bundle goes the other way: the student exports their song with their own bookmarks and notes for you to see.
• Export the sound ("Export sound…" in the player's ⋮ menu): the whole song or the active loop, repeated as many times as you like with its gap and count-in, at the practice speed and pitch and with the sound tools as set, as a FLAC or WAV file the student can play anywhere. The file is named after the song, the loop and the speed; on a phone it goes straight to the share sheet.
• Print the keys: Settings ▸ Keyboard prints every shortcut on one page for the music stand.

6. Lessons, classes and gigs#

• Tags sort a library by student ("Maria", "Tuesday group"), instrument, tuning, grade, or "gig 2026-12". A song carries any number of them.
• Search finds a song by title, artist, album, tag, loop name, bookmark name, lyrics or notes as you type: "all loops named ii–V", "every song with 'bridge' in a bookmark".
• Setlists are ordered lists of songs for a lesson or a gig. "All songs with lyrics" is always the first list; the stage view shows one song's sheet at a time with a Songs panel to detour, and stores nothing itself.
• Sort the library by title, artist, date added or last practised; the library remembers what you were practising and reopens there.

7. Keep the work safe#

• Undo and redo everything, in the song and in the library, with a history page; nothing that can be undone asks "are you sure". Deleted songs, versions and setlists wait 30 days in Recently deleted.
• Back up the library to a folder or an external drive as a dated plain copy; set a reminder; restore after a warning. Settings ▸ Storage shows what is held for safety and frees it.
• Sync between your own devices through storage you already have (an SFTP server, WebDAV such as Nextcloud, or a folder on your computers), optionally encrypted with a passphrase grABloop never sends anywhere. Mark loops on the laptop at home, open the tablet in the lesson and they are there. Sync is for one person's devices, not for sharing with a student: bundles are for that.
• Everything is offline. grABloop collects nothing and sends nothing; the terms and privacy notice in About say so in full.

8. Every student can use it#

• Keyboard: every action has a key, every key can be changed per device, and the sheet prints on one page (KEYBOARD-AND-ACCESSIBILITY.md lists them all).
• Screen readers (VoiceOver, TalkBack) name every control; a key that changes the player says what it did. Large text up to 200 % and less motion are respected.
• English and Greek, switched live in Settings; the student's names and texts stay as written.

9. What comes later#

In the order currently planned (docs/FEATURES.md): a tempo grid with metronome, bar-based count-in and beat-snapped loops (version 1.x); foot pedals and MIDI for hands-free control; call-and-response and pause-repeat practice modes; a practice log per loop (minutes, repeats, tempo reached); stem separation and chord suggestions, offline on the device.

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